Pack mask



FIG. 1 is a front elevational view of a pack mask showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right side elevational view thereof; and,

FIG. 5 is a cross-sectional view thereof taken along lines 5-5 of FIG. 1. 

CLAIM The ornamental design for a pack mask, as shown and described. 